1. Field of the Invention
The present invention relates to a gear transmission assembly for an electrical power tool and including a two-stage gear train located in the housing and having an axially displaceable indexing gear, and a shift device for shifting the gear train from one stage to another and having a shifting slide displaceable from one shift stage to another, and a springable shifting stirrup connected with the shifting slide and cooperating with the indexing gear for displacing same in response to displacement of the shifting slide between shift stages.
2. Description of the Prior Art
Gear transmission assemblies of the type described above are used in electrical power tools in order to adapt a rotational speed of a power tool and, thus, of a used working tool, e.g., a screw bit, drill, etc. . . . to prevailing condition.
German Publication DE 3 904 085 discloses a gear transmission assembly for an electrical power tool and including a multi-stage gear train located in the assembly housing and shifting means for shifting the gear train from one stage to another. The gear transmission assembly includes a shifting slide displaceable between shift stages and a springable shifting stirrup connected with the shifting slide and cooperating with an indexing gear or axially displacing the indexing gear in response to displacement of the shifting slide.
The advantage of the known gear transmission assembly consists in that for shifting the gear train between two stages always a single gear train shift suffice.
A drawback of the known gear transmission assembly consists in that for a gear train with more than two stages, several shifting slides are needed.
Accordingly, an object of the present invention is to provide a multi-stage gear transmission assembly that can be economically produced.
Another object of the present invention is to provide a gear transmission assembly having a gear train with more than two stages with a convenient shifting between the stages.